Postoperative radiotherapy for Stage 1 endometrial carcinoma: Long-term outcome of the randomized PORTEC trial with central pathology review

Abstract

In 2000, the results of the multicenter Post Operative Radiation Therapy in Endometrial Carcinoma (PORTEC) trial were published. This trial included 714 Stage I endometrial carcinoma patients randomly assigned to postoperative pelvic radiotherapy (RT) or no further treatment, excluding those with Stage IC, Grade 3, or Stage IB, Grade 1 lesions. Radiotherapy significantly decreased the risk of locoregional recurrence (4% vs. 14%), without affecting overall survival. In this report the long-term outcome and results with central pathology review are presented. The slides of 569 patients (80%) could be obtained for pathology review. Median follow-up for patients alive was 97 months. Analysis was done according to the intention-to-treat principle. The primary study endpoints were locoregional recurrence and death. Ten-year locoregional relapse rates were 5% (RT) and 14% (controls; p < 0.0001), and 10-year overall survival was 66% and 73%, respectively (p = 0.09). Endometrial cancer related death rates were 11% (RT) and 9% (controls; p = 0.47). Pathology review showed a substantial shift from Grade 2 to Grade 1, but no significant difference for Grade 3. When cases diagnosed at review as Grade 1 with superficial myometrial invasion were excluded from the analysis, the results remained essentially the same, with 10-year locoregional recurrence rates of 5% (RT) and 17% (controls; p < 0.0001). In view of the significant locoregional control benefit, radiotherapy remains indicated in Stage I endometrial carcinoma patients with high-risk features for locoregional relapse.